1. Field of the Invention
The present invention relates to a process kit of image forming apparatus combining a plurality of constituent units such as photosensitive drum and cleaning unit contained in an image forming apparatus such as laser printer of electrostatic transfer type, and more particularly to a process kit mounted on the apparatus main body from above.
2. Description of the Related Art
In the case of an image forming apparatus such as laser printer of electrostatic transfer type, when it is used for a long time, it is necessary to replace the photosensitive drum, and replace or adjust other units, and usually such must be assigned to the serviceman having the professional knowledge.
Recently, by furnishing the apparatus main body with a process kit combining a plurality of constituent units such as photosensitive drum, developing unit and cleaning unit contained in the apparatus, the user of the image forming apparatus can do servicing only by replacing the process kit without asking the serviceman having the professional knowledge.
In such image forming apparatus, the user without professional knowledge can replace the process kit, and hence it is required to do the work as easily as possible.
However, lately, to cope with the trend of smaller size, lighter wight and lower cost of the apparatus, the process kit having the photosensitive drum exposed on the outside is often used. In such process kit, if the photosensitive drum touches the other member when installing the process kit, the surface is easily damaged, and particular attention is needed when mounting the process kit.
Accordingly, in such image forming apparatus, usually, in order that the mounting state can be visually checked by the user when mounting the process kit, and to cope with the thinner trend of the apparatus, the upper part of the apparatus main body is opened, and the process kit is mounted from above the apparatus main body.
Generally, such process kit is provided with a handle member for lifting by the user when mounting. As the handle member to be disposed in the process kit, as disclosed in the Japanese Examined Patent Publication (KOKOKU) No. JP-B2 61-18181 (1986), when the unit for accommodating the toner is assembled in the process kit, a bar shaped handle member extending in the longitudinal direction of the process kit is widely used, which is considered so that the toner may not be shifted to one side when carrying the process kit by holding the handle member, and the handle member is provided in the upper part of the process kit in the process kit of the type for mounting from above the apparatus main body as mentioned above.
The user grips the handle member, lifts the process kit while keeping horizontal in the longitudinal direction, and mounts the process kit on the apparatus main body.
In such conventional constitution, when mounting the process kit, a certain user may hold nearly the middle of the handle member by one hand. However, when the process kit is lifted while keeping horizontal in the longitudinal direction, the supporting state is unstable if the middle of the handle member is supported by one hand, and it is difficult to keep balance as the process kit is heavier and longer. Therefore, when mounting the process kit on the apparatus main body, the balance may be broken, and, for example, the exposed photosensitive drum may be hit against the member of the apparatus main body side, and the photosensitive drum may be damaged. In particular, the supporting position of the handle member is deviated from the middle part, the process kit is installed in an inclined state, and when mounting the process kit the instability increases.
Besides, since the process kit is mounted by the user without professional knowledge, the user cannot judge, after mounting the process kit, if the process kit has been securely installed in the specified mounting position. Hence, without knowing that the process kit has been installed at a position off the specified mounting position, the opened upper part of the apparatus main body may be closed, which may lead to damage of the photosensitive drum or the like.
What is more, when dismounting the process kit and cleaning the constituent members of the image forming apparatus, cleaning members may be provided or prepared separately from the process kit, which is very bothering.